This server calculates the variability in each column of a multiple sequence alignment using the
Shannon entropy (H)
function. H values range from 0 (only one residue in present at that position) to 4.3 (all 20 residues are equally represented in
that position).

In addition, the server allows the user to set a Shannon Filter in order to search the alignment for sequence stretches with
variability (Shannon Entropy, H) under the set value. For more detail information click
here